Aeroplane



UNITED STATES PATENT OFFICE.

CHARLES RICHARD FAIREY, OF HAYES, ENGLAND.

AEROPLANE.

Application filed April 23,

To all whom it may concern Be it known that I, CHARLES RICHARD FAIREY, a subject of the King of Great Britain, and resident of Cranford Lane, Hayes, in the county of Middlesex, England, have invented a certain new and useful Improvement in Aeroplanes, of which the following is a specification.

This invention relates to the control, at will, of the lateral stability of aeroplanes or flying machines which are supported, partly or wholly, by two or more surfaces or planes superimposed one above another and of equal or approximately equal lateral span. For the sake of clearness, the following terms used in this description will be employed in the sense now to be explained. Each complete plane, extending as a whole from side to side of the machine, will be called a deck, and the two half-planes (upper and lower) at one side of the center of the machine will, taken together, be called a wing; the machine being regarded as having a right and a left wing each comprising an upper and a lower plane (in reality an upper and a lower half-plane or half-deck). The outer or lateral extremity of a wing will be called the tip of that wing, and similarly the outer or lateral extremity'of each (half-') plane comprised in a wing will be called the tip of that plane. The gap is, as usual, the vertical distance separating the two hal planes which together constitute a wing, more particularly toward its outer lateral extremity or tip. An aileron is, as usual, a small angularly-movable plane, either independent of both decks or hinged to an upper or a lower deck toward the tip of each wing, and capable of having its inclination varied without of necessity warping either plane of the wing itself. In some cases an'aileron is separate from, and placed in the gap between, the upper and lower planes; but in this description (unless where otherwise stated) an aileron is to be understood as being a hinged portion or extension of the rearward margin of an upper or a lower plane at or toward its tip; ailerons being, as is well known, of two kinds, singleacting and double-acting. A single-acting aileron is capable of being depressed at will below'its normal inclination, the aileron being pulled down positively by the pilot, but returned to its normal inclination automatically either by wind-pressure or by spring- Specification of Letters Patent.

Patented Apr. 20, 1920.

1919. Serial No. 292,163.

power when the pull is released. A double acting or so-called balanced aileron is capable of being, at will, either depressed or raised beyond its normal inclination, such an aileron being in one arrangement depressed positively by the pilot against springpower constantly tending to raise it above its normal inclination, and being in another arrangement pulled downward below or upward above its normal inclination, as required, and also restored to its normal inclination, in each case positively by the pilot.

Assuming the machine to have canted laterally so that one wing has dropped below the level of the other, the depression of an aileron of what for the time being is the lower wing will tend to lift that wing, for the reason that its immediate effect will be to increase the lifting power of that plane of the wing to which the aileron appertains. But, as this increased lifting power involves an increase in the head-resistance offered by the plane in question, the speed of the forward movement of the lower wing (whereof said plane forms part) will be reduced, with a corresponding diminution of the otherwise increased lifting power of the wing. At the same time, unless means are adopted to alter it, the head-resistance ofifered by the planes of the opposite or higher wing of the machine may remain approximately at its original value, with the result that, the speed of the forward movement of said higher wing continuing undiminished, the machine as a whole will tend to swerve from the straight course toward that side at which the (for the time being) lower, and slower, wing is situated.

Several methods of effecting, at will, lateral control in such circumstances, have been proposed for machines having upper and lower decks of equal or approximately equal span. Thus, for example, it has been proposed to fit ailerons to the upper plane alone. But in this case, it is found that the attempt to lift the (for the time being) lower wing of the machine by depressing its aileron has the opposite of the desired effect if the aileron be depressed beyond a very limited range, for the reason that the partial closing of the gap at the lower side of the machine (consequent on excessive depression of the aileron) causes such an increase in the headresistance offered by the wing at that side of the machine that this wing is slowedup and its lifting power is either insufficiently increased or is even reduced; the defect being 7 Efforts to overcome this defect by enlarging the chord of the upper deck have not proved successful, and the usual practice has been either to extend the upper deck laterally, fitting an aileron to each lateral extension (as in certain well known systems of construction), or to fit ailerons to both the upper and lower decks when these are of equal or approximately equal lateral span (as in otherv well known systems). in this connection it is to beobserved that, in cases where an aileron, separate from both the upper and lower decks, is placed in each gap, the general opinion is that equalization of the head-resistance of the respective wings is obtained for only one angle of attack, so that, as this angle is subject to continual variation, equalization of head-resistance under all conditions cannot be said to have as yet been completely attained by the method in question.

According to another well known system, it has been proposed to counteract the tendency to swerve, during the righting operation, toward that side at which the (for the time being) lower wing is situated, by-

automatically steering the machine in the horizontal direction, for which purpose a rudder has been mechanically coupled to the ailerons of both wings in such manner that, on the aileron or ailerons of the (for the time being) lower wing being depressed in order to effect the lifting of that wing, the rudder is automatically moved so as to steer the machine in the direction opposite to that in which it tends to swerve.

The present invention relates to aeroplanes other than monoplanes and has for its object to enable ailerons'to be used for the purpose of efiecting lateral righting at will, in such manner that the head-resistance of the respective wings will be substantially equalized, and that moreover the employment of a rudder mechanically coupled to the ailerons, for the purpose of automatically counteracting the tendency of the machine to swerve during the righting operation, will be rendered unnecessary. With this objectin view, an aeroplane constructed in accordance with the present invention has a double-acting aileron fitted to the lower plane alone of each wing, the decks of the machine being made of equal or approximately equal span, and the means for con trolling the respective ailerons are so connected together that when the one aileron is depressed below, the other will be raised above the normal inclination and vice versa; no direct mechanical interconnection 'be-, tween'the ailerons and rudder being em-.

ployed. The double-acting ailerons may either be moved wholly by the pllot, or may be depressed by the pilot against springpower tending to raise them above their normal inclination.

l/Vith this arrangement,when the machine cants laterally, righting may be effected by simply depressing the aileron of the (for the time being) lower wing, the interconnection between the ailerons having for efiect to simultaneously raise the aileron of the higher wing, with the result that, while the lifting powerof the lower wing is increased, the head-resistance or" the respective wings is more or less equalized. As, therefore, there may belittle or no tendency on the part of the machine to swerve, during the righting operation,'toward that side at which the (for the time being) lower wing is situated, the pilot may find it unnecessary, or scarcely necessary, to manipulate the rudder for the purpose of counteracting such tendency. In these circiunstances, it will be obvious that a direct mechanical interconnection between the ailerons and the rudder might even prove disadvantageous; the more so in case where (as may sometimes occur), the head-resistance of the (for the time be ing) higher wing happens to be increased in a higher ratio than that of the lower wing, since, in such case, the machine may actually tend to swerve toward the higher side, thus rendering it advisable for the pilot to steer toward the lower instead of "toward the higher side during the righting operation.

In the accompanying drawings which illustrate diagrammatically an embodiment of this invention applied to a biplane, F igure 1 is-a front elevation, Fig. 2 is a plan of the lower plane and Fig. 3 isja part side view of the machine drawn to a larger scale showing the right hand .wing in end elevation with its aileron depressed.

As will be seen in Fig. 1 the upper and lower planes a and b respectively are of the same length transversely of the machine and, as will be seen in Fig. 3, they have substantially equal chords. The lower plane of each wing includesin itssuperficial area a hinged aileron 0 extending from the wing tip inwardly through the usual distance, each aileron having secured to it two pairs of levers (Z, e which extend respectively upward and downward from the general plane of the aileron near its hinge f. Attached to the lower levers e, e of each aileron c are branch control cables 9, g which are passed around guide pulleys h, 72. and unite at y to form a single control cable 70, and the cables 70, 7c of the respective ailerons a, care led around guide pulleys m, m and wound from opposite directions around a drum n adapt ed to be rotated by a hand wheel 0. Attached to the upper levers d, (Z of each aileron .0 are. branch control cables 32, pwhich are passed around guide pulleys g, g and united at 1", to form a single control cable .9, and the cables 3, s of the respective ailerons c, c are led around guide pulleys t, t and after being crossed the one over the other, as shown in Fig. 1, are attached to the control cables 7c, is at u, u so that when the drum n is rotated by the hand wheel 0 in one direction the control cable 70 of one aileron c is drawn upon to depress said aileron and the attached control cable 8 is simultaneously drawn upon to raise the other aileron 0 the corresponding control cables 70 and s of the ailerons being relaxed respectively to permit such depression and raising.

I claim:

In an aeroplane having a wing structure comprising upper and lower planes of sub stantially equal span positioned one directly above the other, the combination with double-acting ailerons pivotally connected to the lower plane and forming the rear portion thereof, of an independent control member and connections from said control member to each of said ailerons adapted positively to bend the same downwardly to increase the camber of the lower plane, and to bend the same upwardly to decrease the camber thereof and to decrease the gap between the lower and upper planes, said connections being arranged to bend simultaneously one aileron downwardly and the other upwardly, whereby the increase of head resistance on one wing due to increase of wing camber is balanced by a simultaneous increase of head resistance due to decrease of gap between planes on the other side, said control and connections operating independently of any rudder controls.

CHARLES RICHARD FAIR-BY. 

